This question had me stumped for a while, so I had to give it some thought.
Wish that one of the other 'big guns' on the genus Philodendron would pitch
in, they are the experts! Anyway, here goes with my 'best opinion'!!

These two species ( P. goeldii and P. solimoesense ) do not grow as vines,
for as you say they grow shrub-like high in the canopy. While on this same
trip we did observe two other species of Philodendron that may fit the bill
for you, they were P. linnaei and P. melinonii. They both start off after
germination as a climbing vine, then when they find a suitable spot, they
stop growing as a vine and change into a 'birds nest' form of growth, their
baskets or nests of leaves catching the falling leaves and other garbage as
nutrients for their arboreal root systems. I did not observe any large
roots extending from these 'birds nests'-type of Philodendron trying to
reach the ground, they seemed dependant on their 'nests' to catch the
falling leaves as nutrients. SO--though I did not observe this myself, I
see no reason why a seed of a species like one of these could NOT be
deposited and germinate in a suitable tree crotch or hole in a trunk, then
the seedling would grow to a suitable point on the trunk or branch, where it
would then grow into the birds nest shape, needing no contact with the
ground.

I also thing that more observations on the vine-type species of
Philodendron, Monstera and the like would be in order, as though many grow
upward as vines/climbers after germinating on the ground (or even maybe in a
tree-hole or higher crotch in a tree), many or all that I can think of still
send their roots downward to the soil for water and nutrients, seemingly
unlike the birds-nest species I mentioned.

Thanks for the kind note. Do either of these Philodendron species actually
grow as vines, though? That some aroids can be epiphytes is clear, that is
they grow shrub-like at one spot in the canopy. My question concerns
whether vine or vine like species ever sprout in the treetops. Vines are
usually thought of as always sprouting on the ground and growing upwards.
Any thoughts?

Best,

Mark<<

>Dear Mark,
>
>I have recently returned from Fr. Guiana, and something we observed on this
>trip and our discussions we had there were along these lines. Although I
>have no 'for-sure' answers to your querry, I will offer my thoughts on this
>as they may be helpful. Two of the Philodendron species that we were
>especially eager to see in their natural conditions were P. goeldii and P.
>solimoesnse, both 'self headers' that are seen normally as 'potted plants'
>in shows or private collections. Our host, Joep Moonen of Emerald
>Jungle>Village, who runs eco-tours with a guest house, and who is an expert
>on all
>the Aroids and Bromeliads (plus MANY other groups such as Reptiles ) of S.
>America, knew exactly where these two species could be viewed under
>completely natural conditions. This was great, as we would NEVER have
>located the few specimens that we were able to see under his guidance!!
>Unless found by sheer luck within the remains of a fallen jungle giant
tree,
>they are only seen (so far??) growing as epihytes in the croych of a huge
>trees, way up in the canopy, but with strong roots reaching down 50 mts
(150
>ft.) and more to feed on the forest floor! Joep says he has not found
>these species growing low down under 'natural' conditions, but did show us
>a>plant of P. solimoesnse that had established itself at ground level and
>was
>growing well several years after being 'forced' down by the felling of the
>tree upon which it had been growing many years ago, and which had been
>felled when the road was being constructed. To add to this, I had seen
aTV
>Nature show a short while ago where spider monkeys were shown feeding on
>>the ripe fruits of P. goeldii in the canopy, and I wondered if their was
>some 'barrier' to the seeds from this fruit germinating and growing if and
>when the seeds passed through this monkey, or perhaps a bird on to the
>forest floor (perhaps not enough light this low down to sustain growth??).
>On the other side of the coin, I feel sure that the opposite will and does
>occur, i.e. that the fruits of 'normally' ground-growing species are
>sometimes passed out high in the canopy into a subitable growing medium,
>such as the crotch or hole in a trunk, and will grow and survive there for
>a>while if conditions are right for their survival, such as enough
moisture,
>etc.. I ponder how long they may survive, as since they are
>'normally'-ground-level growing plants, if they would have evolved the
>strategy of the long, ground/moisture/nutrient-seeking roots we saw in the
>species I mentioned previously, which obviously allows these highly adapted
>species to live and reproduce for MANY years , perhaps centuries, high up
in
>the canopy, surviving flood and drought till their supporting 'mother' tree
>>dies or is blown over. Perhaps the ground-living species would not
>survive
>the once-every-ten/fifty-years
> ( ? ) drought that may occur in this jungle, so that they are eventually
>eliminated from the canopy from time to time even IF they manage to grow
>there by accident every so often.
>Hope that this is of help, and that it may elect other comments/ideas from
>others on our list.
>
>Cheers and good luck,
>
>Julius Boos
>W.P.B., Florida.
>ju-bo@msn.com
>>
>>>I am finishing an invited paper for the journal BIOTROPICA on the
>>terminology of canopy biology. I am wondering whether there is such a
>>thing as a vine (or similarly a 2ndary hemiepiphyte) that can be an
>>"accidental epiphyte" by sprouting sometimes in the canopy say in the
>>soil of a branch crotch, rather than on the ground. In flooded or
>>innundated forests this might even be common, I should think.
>>
>>I'm hopeful you can send this question out to the aroid community in
>>case anyone has seen examples. This would be a new and interesting type
>>of behavior.
>>
>>I'll send the same e-mail to Don Burns in case you are not around.
>>Would love any thoughts on this.
>>
>>best,
>>
>>mark
>>
>>Mark W. Moffett
>>respond to: moffett@uclink4.berkeley.edu
>>University of California at Berkeley, Integrative Biology
>>

see no reason why a seed of a species like one of these could NOT be
deposited and germinate in a suitable tree crotch or hole in a trunk, then
the seedling would grow to a suitable point on the trunk or branch, where it
would then grow into the birds nest shape, needing no contact with the
ground. >>

Julius et al.,

Reminds me of the very unusual situation in Greensburg, Indiana where a
deciduous tree had germinated in a gutter high on the county courthouse's
roof! It grew so large and had become a popular tourist postcard so that the
county routinely trimmed it into dimensions that did not exceed the
weight-bearing ability of the gutter and soffit! It was there for decades -
and may still be!